coap_io.c: Updates for esp-idf port

include/coap3/coap_mutex.h

@@ -46,6 +46,7 @@ typedef mutex_t coap_mutex_t;
 
 #else
 /* define stub mutex functions */
+#warning "stub mutex functions"
 typedef int coap_mutex_t;
 #define COAP_MUTEX_INITIALIZER 0
 #define coap_mutex_lock(a) *(a) = 1

src/coap_io.c

@@ -1132,7 +1132,9 @@ coap_io_prepare_io(coap_context_t *ctx,
   coap_session_t *s, *rtmp;
   coap_tick_t timeout = 0;
   coap_tick_t s_timeout;
+#if COAP_SERVER_SUPPORT
   int check_dtls_timeouts = 0;
+#endif /* COAP_SERVER_SUPPORT */
 #ifdef COAP_EPOLL_SUPPORT
   (void)sockets;
   (void)max_sockets;
@@ -1173,8 +1175,10 @@ coap_io_prepare_io(coap_context_t *ctx,
         if (timeout == 0 || tls_timeout - now < timeout)
           timeout = tls_timeout - now;
       }
+#if COAP_SERVER_SUPPORT
     } else {
       check_dtls_timeouts = 1;
+#endif /* COAP_SERVER_SUPPORT */
     }
   }
 #if COAP_SERVER_SUPPORT